It is known from old days that there has been a system that extracts power from a displacement type engine to the outside of the engine by installing a displacement type motor or an exhaust turbine capable of converting pressure energy remained in exhaust gas into rotating power to an exhaust port of a displacement type engine. As shown in a reference Japanese Patent document 1 for example, there is a recent proposal on a regenerating device that is provided with a valve for adjusting flow rate of introduced gas by configuring a regenerator as a volume expanding device. However, the reference document 1 does not mention any displacement type engine suitable for installing a regenerator. Henceforth, such a device that converts pressure energy remained in exhaust into power is referred to as a regenerator, whereas the pressure at an exhaust port that is equal to the pressure at the inlet of the above regenerator is referred to as regenerating pressure.
Although not generally used, as shown in a reference Japanese Patent document 2 for example, such an internal combustion engine that completes one cycle via six strokes comprising (1) suction, (2) compression, (3) explosion/expansion, (4) exhaust, (5) introduction of scavenging air, and (6) scavenging air exhausting stroke, is known as a scavenging engine. Of these, such a conventional scavenging engine that is equipped with one exhaust port cited in this document is referred to as a six-cycle engine hereinafter.
As cited in a reference Japanese Patent document 3 for example, it is known that there is an engine that is equipped with an exhaust turbine functioning as a regenerator provided for a six-cycle diesel engine that uses (5) a water-injecting and expanding stroke for the fifth stroke instead of using (5) introduction of scavenging air. However, as cited in FIG. 2 of the reference Japanese Patent document 3, the pressure at the exhaust port is equivalent to the pressure at the suction port, and yet, there is neither any description nor suggestion on a mechanism that regenerates more substantial pressure energy from exhaust gas by increasing the regenerated pressure.
It is known that there is a “free-piston type gas turbine” called “Pescara Cycle”, which is a gas turbine engine using a reciprocating piston engine as a combustion chamber. A reciprocating piston engine is a kind of displacement-type internal combustion engines.
As cited in a reference Japanese Patent document 4 for example, it is also known that there is a system which initially causes angle of vane constituting a nozzle of an exhaust turbine to vary continuously, and then causes aperture area of a turbine nozzle to be varied and further causes area of gas passage to be varied, thereby enabling the system to be adapted to variable gas volume. A gas turbine with variable number of nozzles has been disclosed in a patent application that is utilized for the basis for the claim of priority in the present application for a Japanese patent.
In terms of a hybrid vehicle, it is known that there is a series hybrid vehicle which initially converts all power output from an internal combustion engine into electric power and then drives a vehicle driving motor to make the series hybrid vehicle run. As cited in a reference Japanese Patent document 5 for example, it is also known that there is a parallel hybrid vehicle which is driven not only by power output from an internal combustion engine via a transmission, but also driven by a motor with power from a battery by directly linking the motor to an output shaft of the internal combustion engine.
Further, as cited in a reference Japanese Patent document 6 for example, it is also known that there is a hybrid vehicle which initially distributes power output from an internal combustion engine via a planetary gear, and then drives the hybrid vehicle with a portion of the output power and simultaneously drives a generator that concurrently serves as a motor by applying remaining power to generate electric power. Said vehicle further utilizes a torque distribution system using a couple of motors capable of driving another motor connected to driving wheels by applying the generated power and the battery power and further using planetary gears, thereby the above-cited hybrid vehicle incorporates both characteristics of the series type and the parallel type.